


The Predicament

by PineByPine (Tyrannosaurus_Sex)



Series: Three Saplings (A Triplets AU Series) [1]
Category: Gravity Falls
Genre: Aged-Up Character(s), Multi, Threesome - F/F/M, Triplets
Language: English
Status: Completed
Published: 2019-07-05
Updated: 2019-07-05
Packaged: 2020-06-10 09:45:36
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,615
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19499920
Author URL: https://archiveofourown.org/users/Tyrannosaurus_Sex/pseuds/PineByPine
Summary: Mabel and her sister Ty are in trouble. They've got stuff figured out between themselves, but they don't know if their brother Dipper is possibly on the same page.





	The Predicament

**Author's Note:**

> I guess this series requires a little "buy in" but I think it's worth it. I don't know who originated the "Triplet AU" idea but I found it through work of doublepine. The previously established AU is one that features Mabel, Dipper, and Tyrone. I felt if I was going to write in this space, I wanted my own space to play. One gender flip later, and this AU was born. It was a really enjoyable series to create, maybe even one of the fan works I'm most proud of.

Dipper had attempted to knock on his sisters’ door but it wasn’t latched and had swung open instead. Ty was at the desk and Mabel propped up on her elbows on the bed, both were now giving him quizzical looks.

“You need something, broseph?”

Dipper tightened his grip on the towel around his waist, making doubly sure it was secure. “Uh yea, sorry. I just wanted to let you know the shower was free.”

Mabel rolled her eyes dramatically. “We’ve been up for like four hours already. Not everybody sleeps till noon every chance they get.”

Ty gave her brother an easy smile. “Thanks, but we’re good, Dip. Get the door, will you?”

“Oh, sure.” Dipper reached in and pulled the door shut behind him.

“I don’t think he’s realized,” Mabel smirked as she returned to reading the latest issue of Sexy Vampire Weekly, “that we’ve been showering early ever since he started with the whole ‘ungodly long showers’ thing. The amount of hot water that dude uses is bonkers.”

Her sister shifted in her chair and returned to her AP calculus homework, punching keys into the calculator on the desk and scratching at the numbers in her notebook.

Mabel tapped a finger against her chin and looked up at the ceiling for a moment, trying to recall something. “Did Dipper actually take two showers yesterday?”

With a sudden motion, Ty flipped her notebook closed, flung herself from her chair, and flopped face down onto her own bed. “Can’t take it anymore.” She declared. “Too distracted for homework.”

Mabel closed her magazine and rested her chin on a palm. “Distracted, eh?” She played innocent. “What on earth could have my little sister so distracted?”

Ty lifted her face from the bed and gave her sister a grave look. “Are we actually talking about this or are you just being cute?”

The older girl pushed herself up from the bed. She started to count off on her fingers. “First off, I’m always cute. Second, you and I already agreed to be honest about this and third…” She grabbed her sister by the shoulders and pulled their faces level. “Oh my god did you see that freaking happy trail?! I couldn’t not look; it was like it was calling to me, girl!”

Ty’s cheeks reddened at her sister’s words and she tried to hide behind her hands. “I know. I know. It was all I could do to keep my cool. How are we supposed to act normal with all that cheesecake just walking around the house?”

“Do you think he knows? I was a total train wreck. ‘Not everybody sleeps till noon every blah blah blah.’” She mocked her own voice. “I would totally sleep until noon if I could! Sleeping-in is the business!”

“You!?” Ty boggled at her sister. “What about me? There was no way he didn’t notice me staring at him. God I was so obvious.” She smacked her forehead. “Learn some subtlety, Ty!”

Mabel cast herself back onto the bed, flailing her arms. “What are we going to do?” She despaired. “We can’t keep this up! We’re gonna get caught and then KA-BOOM,” she make a dramatic sweep of both her arms to add visual emphasis, “everybody figures out what horrible perverts we are.”

“We need those blinders they put on horses.”

“Or blindfolds.”

“Ooh!” Ty enthused. “Or we just wear mirrored sunglasses all the time. Everybody thinks were just being cool and stuff but really we’re spending all our time just taking in eyefuls.”

Her sister giggled. “Oh, that is the best of both worlds. It doesn’t just solve the Dipper-problem, either. You, little missy,” Mabel elbowed her sister in the ribs, “have been driving me batty for weeks. You leaned over the table at dinner last night and I'm 'dang girl' and trying by best not to look down your shirt.”

Ty gave her a shove. “Like you’re one to talk with those shorts you’ve been wearing lately. I’m surprised I’m not in the shower more often than Dipper.” She got a mischievous grin. “And I’m doubly glad that mom or dad haven’t figured out why we wanted that detachable shower head.”

Mabel got a dreamy look in her eyes. “Mr. Squeaky-Clean™, you’re the best boyfriend.” Then her eyebrows scrunched together. “Wait, do you think that’s what’s been dragging out Dipper’s shower time? Is Squeaky cheating on us?”

Ty eyed her incredulously. “Really? You’re just now figuring this out?”

Mabel’s jaw dropped. “You’re saying you knew?!”

“I figure it was something like that.” The other girl shrugged. “Although probably not Mr. Squeaky-Clean™, considering the rather copious and conspicuously unexplained bottle of lotion that has appeared in the bathroom.”

“Oh,” recognition spread across Mabel’s face, “ohhhhhhh. Dipper, you perv.”

“I just figured it was pretty typical teenage-boy behavior. Harper Robinson always used to complain about her brother leaving dirty tissues all over the place.”

Mabel made a face of disgust at that. “What? Like he just - you know. Then wipes up the stuff and litters the house with it?”

“Apparently.”

Mabel clapped her hands over her eyes. “Ugh, at least the Dipster isn’t making a mess.”

“Well, if you’re anything like me,” Ty sighed, “and I have many reasons to expect that you are, then you’re probably going to wish you didn’t know about what our dear brother was up to during his daily ablutions.”

“Why? It’s just Dipper taking things into his own hands. If it weren’t awkward, I’d give the dude a high five on the way out.”

The blush that had started on Ty’s cheeks earlier hadn’t stopped it’s march across her skin and now had officially bridged her nose, forming one large red splotch across the middle of her face. “Because now that you know, when you notice him go in there…”

Mabel waited for her sister to continue and the pause grew longer and longer.

The middle triplet made frustrated growling now. “When I know he’s in there and what he’s probably doing I can’t freaking stop myself from picturing it and it gets really frustrating. Like _really_ frustrating.”

Mabel considered this and, since she was indeed very much like her sister, started picturing it as well. “Oh. Yes.” It was Mabel’s turn to blush now. “Yeah, you’re right, sis; we’re totes screwed.”

They both sat in silence for a while, thoughts no longer exactly in the present.

“Wait a sec.” Mabel finally broke the silence.

“Yeah, Mabes?” Ty rose and propped her head up with one arm. “Have you happened upon some solution to our little predicament?”

“Just a thought.”

“Well, don’t keep it to yourself.”

“So you and I, we’re both like both going on overdrive lately. And the sort of junk that makes us go all…” she voiced and mimed an imitation of starting a motor with a pull cord and then throttling it all the way up. “It’s not exactly got the normal set of ‘no, not that’ filters going on.”

“Agreed, thus our current situation.”

Mabel sat for a second. “How different do you figure Dipper is from us?”

“Well, he’s a dork. And he gets all introspective and freezes up. And he’s probably the least athletic...”

“I meant on the” insert motor revving noise, “thing, dummy.”

Ty’s eye went a little wide. “Oh, ohhhhh. I don’t know; I just thought that you and I were weird. No reason to suppose that Dipper shares are peculiarities.”

Mabel got up and sat cross-legged. “And up until you and I had our heart-to-heart, I thought I was the only one going all crazy, but now it’s two out of three and the odds are in our favor.”

“I don’t think that’s how statistics works, Mabel.”

The older triplet made a dismissive motion with her hand. “Pshhh. Dipper’s an odd duck but he’s still a Pines triplet, through and through, and if this is what it means to be a Pines triplet, he’ll be right here with us. It’s worth trying.”

Ty considered for a moment before answering. “It’s a big risk, but on the other hand it was a big risk opening up to you. And that’s turned out pretty well. At least we can talk freely now and help each other out.” To this Mabel winked in response and Ty blurt out a laugh. “Yes, fine. Double entendre intended.”

“And think about poor Dipper out there.” Mabel indicated toward the door. “Living in a house with the two hottest girls on the planet. Can’t talk about it. Can’t act.” Her eyes were as big a saucers, filled with pathos. “He’s struggling all the time, and you and me, Ty Pines, we’re the only ones who can help him.”

Her sister raised an eyebrow conspiratorially. “And help ourselves while we’re at it?”

“Bonus!”

“If we’re going to approach this, we’re going to have to go about it delicately. We can’t just ambush him the next time mom and dad are out of the house. We need to set this up so he has an out and that if it turns out you’re wrong and we’re just weirdos, we’ve got something ready to cover for us.”

“My sister the pessimist.” Mabel scoffed.

“Dipper’s the pessimist; I’m the realist.”

“Does that make me the optimist?”

Ty wrapped her arms around Mabel and dragged her down to the bed. “You’re the surrealist, Mabes.”

They kissed.

“That’s it!” Ty declared with a start, jumping up to flip the lock on their door. “I can’t take it; we’re going to have to risk a daylight session.”

Mabel was already whipping off her shirt and laughing. “Yes! I’ve been hoping you’d break down since before Dipper came in here.”


End file.
